Unverified Commit 00b24250 authored by Björn Töpel's avatar Björn Töpel Committed by Palmer Dabbelt
Browse files

scripts/decodecode: Add support for RISC-V 

RISC-V has some GNU disassembly quirks, e.g. it requires '-D' to
properly disassemble .2byte directives similar to Arm [1]. Further,
GNU objdump groups RISC-V instruction by 2 or 4 byte chunks, instead
doing byte-for-byte.

Add the required switches, and translate from short/word to bytes when
ARCH is "riscv".

An example how to invoke decodecode for RISC-V:
  $ echo 'Code: bf45 f793 1007 f7d9 50ef 37af d541 b7d9 7097 00c8 (80e7)
  6140' | AFLAGS="-march=rv64imac_zicbom_zihintpause"  \
  ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- ./scripts/decodecode
  Code: bf45 f793 1007 f7d9 50ef 37af d541 b7d9 7097 00c8 (80e7) 6140
  All code
  ========
     0:   bf45                    c.j     0xffffffffffffffb0
     2:   1007f793                andi    a5,a5,256
     6:   f7d9                    c.bnez  a5,0xffffffffffffff94
     8:   37af50ef                jal     ra,0xf5382
     c:   d541                    c.beqz  a0,0xffffffffffffff94
     e:   b7d9                    c.j     0xffffffffffffffd4
    10:   00c87097                auipc   ra,0xc87
    14:*  614080e7                jalr    ra,1556(ra) # 0xc87624          <-- trapping instruction

  Code starting with the faulting instruction
  ===========================================
     0:   614080e7                jalr    ra,1556(ra)

[1] https://sourceware.org/bugzilla/show_bug.cgi?id=10263



Signed-off-by: default avatarBjörn Töpel <bjorn@rivosinc.com>
Tested-by: default avatarAlexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20230119074738.708301-3-bjorn@kernel.org


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent eb165bfa

scripts/decodecode

+11 −1
Original line number Diff line number Diff line
@@ -93,6 +93,11 @@ disas() { 
		${CROSS_COMPILE}strip $t.o

	fi



	if [ "$ARCH" = "riscv" ]; then

		OBJDUMPFLAGS="-M no-aliases --section=.text -D"

		${CROSS_COMPILE}strip $t.o

	fi



	if [ $pc_sub -ne 0 ]; then

		if [ $PC ]; then

			adj_vma=$(( $PC - $pc_sub ))
@@ -126,8 +131,13 @@ get_substr_opcode_bytes_num() 
	do

		substr+="$opc"



		opcode="$substr"

		if [ "$ARCH" = "riscv" ]; then

			opcode=$(echo $opcode | tr ' ' '\n' | tac | tr -d '\n')

		fi



		# return if opcode bytes do not match @opline anymore

		if ! echo $opline | grep -q "$substr";

		if ! echo $opline | grep -q "$opcode";

		then

			break

		fi